This invention relates to esterified orgotein.
Orgotein is the non-proprietary name assigned by the United States Adopted Name Council to members of a family of water-soluble protein congeners in substantially pure, injectable form, i.e., substantially free from other proteins which are admixed or associated therewith in the sources thereof. U.S. Pat. No. 3,758,682 claims pharmaceutical compositions comprising orgotein.
The orgotein metalloproteins are members of a family of protein congeners having a characteristic combination of physical, chemical, biological and pharmacodynamic properties. Each of these congeners is characterized physically by being the isolated, substantially pure form of a globular, buffer and water-soluble protein having a highly compact native conformation which, although heat labile, is stable to heating for several minutes at 65.degree. C. at pH 4-10. Chemically, each is characterized by containing all but 0-2 of the protein aminoacids, a small percentage of carbohydrate, no lipids, 0.1 to 1.0% metal content provided by one to five grams atoms per mole of one or more chelated divalent metals having an ionic radius of 0.60 to 1.00A., and substantially no chelated monovalent metals or those that are cell poisons in the molecule.
The aminoacid composition of the orgotein congeners is remarkably consistent irrespective of the source from which it is isolated.
Table I lists the distribution of aminoacid residues, calculated for a molecular weight of 32,500 of several orgotein congeners.
TABLE I __________________________________________________________________________ AMINO ACID COMPOSITION OF SEVERAL ORGOTEIN CONGENERS [Residues per mole, M.W. = 32,500] __________________________________________________________________________ Red Blood Cells (RBC) Liver, Guinea Aminoacids Beef Beef Sheep Horse Pork Dog Rabbit Rat Pig Chicken Human Range __________________________________________________________________________ Alanine 19 19 18 18 18 16 19 22 22 23 22 16-23 Arginine 8 8 10 6 8 8 8 7 8 8 8 6-10 Aspartic acid 37 36 35 35 31 29 34 30 34 36 37 29-37 Cystine-1/2 6 6 6 6 6 6 6 6 4 10 8 4-10 Glutamic acid 21 23 22 30 28 30 25 38 29 26 28 21-38 Glycine 53 52 52 51 52 53 54 54 53 56 51 51-56 Histidine 16 16 14 20 16 15 17 20 15 17 14 14-20 Isoleucine 18 18 18 14 16 18 16 16 18 15 17 14-18 Leucine 17 17 17 18 16 16 19 12 17 15 20 12-20 Lysine 22 21 23 26 23 20 21 18 20 21 23 18-26 Methionine 2 2 2 2 2 6 3 4 2 3 1 1-6 Phenylalanine 8 8 7 9 8 8 9 6 8 8 8 6-9 Proline 12 13 15 10 10 10 13 10 12 13 12 10-15 Serine 17 17 14 14 13 20 18 18 18 15 19 13-30 Threonine 26 25 20 16 27 20 21 17 17 18 18 16-27 Tryptophan.sup.1 Nil Nil Nil Nil Nil Nil Nil Nil Nil 1 2 0-2 Tyrosine.sup.2 2 2 2 Nil 4 2 Nil 2 Nil 2 Nil 0-4 Valine 33 32 31 29 29 34 31 35 32 30 30 29-35 Total 317 315 306 304 307 311 315 315 309 317 318 304-318 __________________________________________________________________________ .sup.1 Colorimetric determination .sup.2 Average of amino acid analysis and spectrophotometric determination.
It can be seen from Table I that orgotein congeners have from 29-37 aspartic acid and 21-38 glutamic acid groups. The present invention is directed to orgotein derivatives in which at least a portion of these aminoacid residues in free acid form are esterified.
As will be apparent to those skilled in the art, some esterification reagents and conditions are capable of simultaneously alkylating free amino groups in the orgotein molecule and esterifying carboxylic acid groups. Such N-alkylated esterified orgoteins are the subject of the application filed simultaneously herewith entitled "N-alkylated orgotein" (Ser No. 611,657) and are part of the instant invention, whose alkylated groups are limited to --COOH groups and whose free amino groups are primary groups, i.e., unalkylated.